1. Field of the Invention
This invention relates generally to wire drawing dies, core tubes, extrusion tips, enameling dies, and the like, of the type employing natural or man-made single crystal and polycrystalline diamonds, cubic boron nitride, or any other hard, wear-resistant material suitable for use as the hard insert element, and to methods of mounting such elements.
2. Description of the Prior Art
Wire drawing dies, core tubes, extrusion tips, enameling dies, guides, nozzles, and other wear-resistant parts employing natural or man-made single crystal and polycrystalline diamonds, cubic boron nitride, or other hard, wear-resistant material as the insert element have been manufactured for some years, typically comprising a metal casing in which the hard insert element is mounted, the casing being adapted to be mounted in a wire drawing machine, insulation extrusion machine, or the like. U.S. Pat. No. 4,129,052 assigned to the assignee of the present invention, and U.S. Pat. No. 4,365,502, also assigned to the assignee of the present invention, disclose prior wire drawing dies and methods of making such dies.
Present methods of assembling wire drawing dies, core tubes, and the like, involve the application of heat and pressure to melt powder metal so as to encapsulate the hard insert element. With the use of present methods, it has been found that a shift in the axis of the insert element may occur during the application of heat and pressure which may result in destruction of the insert element during drilling. It is therefore desirable to provide a method of mounting a hard insert element in which the axis of the element is accurately located concentric with the casing and in which minimum shift of the element occurs during the application of heat and pressure.
A core tube is used in extruding insulation over wire and includes a hard insert element which serves as a wire guide to keep the wire centrally located so as to provide uniform insulation thickness.